Free Catalyst Synthesis of GaN Nanostructures on Si- Substrate via CVD

In this article gallium nitride (GaN) nanostructures have been grown through chemical vapor deposition (CVD) on Silicon substrate, no metal catalyst was used. A high purity of gallium nitride powder was evaporated at 1150 degrees C for 3 hour and then annealed at temperature 1000 degrees C under flow of ammonia (NH3) gas. XRD shows the diffraction peaks located at 2 theta = 32.4, 34.4, 36.8, 48.1, 57.8, 63.5, 68.3, 69.2 degrees corresponding to the (100), (002), (101), (102), (110), (103), (200) and (112) diffraction planes of the product. These results revealed that the diffraction peaks can be attributed to the hexagonal GaN phase with lattice constant of a = 3.189 angstrom and c = 5.200 angstrom. Raman scattering spectrum shows four phonons mode correspond to GaN nanostructure are detected at 560, 570, 720 and 740 cm(-1) corresponding Ei(TO), E-2(high), A(1)(LO) and E-1(LO) respectively. Photoluminescence (PL) of the GaN nanostructure exhibited two emission peaks, a weak and broad ultra violet (UV) light emission peak at 390 nm and a strong yellow light (YL) emission peak at 550 nm.